I'm a level 8 Nord Warrior with full steel armor and a one-handed Elven Sword that deals 16 damage. All I did to kill the first Frost Troll you encounter (the one on the steps leading to Higher Hrothgar, the monks) was have Flames in the left hand and my Elven Sword in the right. Now keep in mind, my steel armor made it so that I can be hit with three regular hits from him, or two powerful hits. My armor rating is 138, and my health is at 130.
So anyways whatWhat I did was just quickly burn the Frost troll and swing my sword once -- only once because a second swing could take enough time for him to hit you. Flames does damage-over-time which means he will burn for about a second. Make sure you see him burning, this is after you use the spell on him for about half of a second. While he's burning, what you do is move close enough for him to swing at you, jump back, and swing once at him after he is done swinging. Be careful as he may swing twice in a row. This makes it so that you can safely hit him after he tries to hit you; this guy does a crapload of damage.
You don't necessarily have to be wearing steel armor; I dodged most of his attacks easily. You also do not need any training in Destruction. I did this with level 15 Destruction, which is what your Destruction starts asat.